Process for purification of hydrocarbon oils



Patented June 24, 1930 UNITED sTATEs PATENT OFFICE manner a. u. wanna, or wnszrrmrn'nnw Teaser, nssreuon'ro STANDARD 1 om'nnvnnormr COMPANY, A conron-n'rron or DELAWARE PROCESS FOR P UBIIICATION 0F HYDBOCARBON OILS no mums. l

The present invention relates to the art ofpurifying and refining hydrocarbon oil and more specifically comprises an lmproved proc-' 'ess for sweetening hydrocarbon oil such as heavy naphtha kerosene, and the like. My invention will e fully understood from the following description.

Hydrocarbon oils such as heavy naphtha, kerosene-and the like often contain sulphur bearing impurities the presence of which is detected by the doctor test. This test is well known in the troleum indust-r has been full described in Technical aper 323 of the U nited States Bureau of Mines, page 83. Oils-which do not pass th s test are termed sour.oils and 'it is customary to treat such oils with doctor solution, which is a solutiqn of litharge in ueous caustic soda and which is also calle sodium plumb te. Treatment with doctor'comprises agltation of the oil with the required quantity of doctor solution for a short time, followed by the addition of sulfur. If sufiicient doctor is' found that if sulfur is added during the blowing treatment in other than small quantities the oil is contaminated by the formation 0 sulfur compounds, as indicated by discoloring on shaking with a small quantity of metallic mercury, and by the fact that the sulfur content of the oil is increased, both of which are undesirable. My improved process reduces the quantities of both doctor, and sulfur used in treating, does not appreciably increase the sulfur content of the oil, and

the oil does not sensibly darken on shaking with mercury and is much improved in respect to color holding properties and burnin quality.

n m process less than that quantity of doctor solution required to sweeten a samandl is required, but if the mix Application med August 19, 1927. Serial No. 214,215.

ple of oil to be treated is added to the oil but I preferably use not more than and generally between 10 and 50% ofthat required. Bdythat required, I mean the quantity of octor necessary to sweeten the oil in the absence of a current of air or other oxygen containin gas. The mixture is agitatedby any suita le means and in most cases the current of air is sufiicien't for agitation. Agi tation is continued from 4 tov 10 hours, depending on the nature of the oil.

The mixture ofoil and doctor is preferably blown with air for about one hour before addition of sulfur and sulfur is then added in a-plurality of batches with a blowing period after each addition. I prefer to add the vmajor quantity of sulfur in-the first two batches which are preferably equal to one half that required to react with the lead oxide in the, doctor. Subsequent batches of sulfur ing 2 pounds of sulfur per 1000 barrels of oil being treated. The small subsequent batches of sulfur are added untilvthe oil is sweet and .blowin with air is continued for about one hour a er each addition.

As an example of my process the following is illustrative. A sour rerun kerosene from Regan crude has the following character istics Gravity 42.5 A. P. I." Sulfur content. Q. 100% Color 19 Saybolt Color after 1 hours at 212 F- 14 Saybolt rent of air for about one hour. The major quantity of sulfur is then added in two batches of 288 pounds each, followed by blowing for about one hour. The oil is 70 V are relatively small preferably not exceedfound to be sour and requires two further" Gravity 425 A. P. I Doctor Passes Sulfur content ..103% Color 2l Saybolt Color after 16 hrs. at

212 F -19 Saybolt Corrosion copper strip -0. K. Mercury test Very slight, passable My invention is applicable primarily to very sour oils but maybe used in sweetening only slightly sour oils. It may be used to sweeten kerosene and various heavy naphthas. My. invention is not to be limited by a theory of the mechanism of the various chem- 'ical reactions, nor by any example given merely by way of illustration, but only by the following claims, in which I wish to claim all novelty inherent in my invention.

I claim:

1. An improved process for treating hydrocarbon oil, comprising agitating with litharge and aqueous caustic soda, blowing a strong current of an oxygen containing gas through the mixture and successively adding small quantities of sulphur during the blowing, whereby the formation of undesirable sulphur compoundsis substantially prevented.

2. An improved process for sweetening hydrocarbon oil, comprising a itating with doctor, simultaneously blowing a strong current of air through the mixture for a prolonged period and successively adding small quantities of sulphur durin blowing whereby the formation of undesira le sulphur compounds is substantially prevented.

3. An improved process for refining sour hydrocarbon oil, comprising agitating with doctor, in quantity less than sufiicient to sweeten the oil in the absence of oxygen, blowing a strong current of air through the mixture for a prolonged period and adding sulphur in successive small quantities during the "blowing whereby the formation of undesirable sulphur compounds is substantially prevented.

4. An improved process for refining sour hydrocarbon oil comprising adding doctor solution not in excess of 50% of that required in the absence of air blowing, blowing with a strong current of air, adding sulphur in small regulated amounts and continuing the blowing whereby'formation of undesirable; silphur compounds is substantially preven e The oil' '5'. A process according to claim 4 in which the mixture of oil and doctor is blown with air for a prolonged period after each addition of sulphur.

6. A process according to claim 4 in which I by about one hour air blowing, said batches not exceeding .072 pounds per pound of litharge, and thereafter adding sul hur in relatively small hourly batcheseach ollowed by air blowing for about one hour until the oil is sweet.

8. A process according to claim 7 in which the relatively small subsequent batches of sulphur are not in excess of 2.5 pounds per 1000.barrels of oil treated.

HERBERT G. M. FISCHER. 

